Pie chart from a summary report

Hello Smartsheet Sages - I'm trying to add a pie chart to a dashboard that illustrates revenue data from 3 different product lines, however, I am unable to select the pie chart as an option. The data lives in a summary report. I select the report, select the columns that I want (which are totals of YTD revenue per area), but the pie chart is greyed out. Columns are formatted as currency. Any ideas?